Accuracy of local television station weather forecasts for boating

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Dutchman
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Accuracy of local television station weather forecasts for boating

Postby Dutchman » Tue Apr 10, 2018 11:11 am

[In another thread on another topic, a this topic was introduced. I have separated this sidebar topic to its own thread, which discusses the accuracy of local television weather broadcasts--jimh]

ASIDE to Jim--that is local news for you, they must fill up that half hour and their weatherman or gal says the sun will shine with a chance of rain.
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Re: Accuracy of local television station weather forecasts for boating

Postby jimh » Tue Apr 10, 2018 12:30 pm

DUTCH--As far as weather reporting on local television stations, that is probably the thing they do best, as they tend to report actual data they scrape off government websites. Behind the on-camera presenter, there is usually someone with a science degree in meteorology gathering and analyzing the weather data. Sometimes that guy is even on camera, too. I can think of one station that I am familiar with where there are two weather guys that appear on camera. They both have master's degrees in science from respected universities like Michigan or M.I.T., so I wouldn't think they'd be considered lightweights when it came to weather reporting.

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Re: Accuracy of local television station weather forecasts for boating

Postby Dutchman » Wed Apr 11, 2018 9:18 am

Too often these local stations are 50 miles from where I want to have the weather predicted.

Technology used aby these degreed-meteorologists quite often is generalized to cover all.

Here in West Michigan their is quite a difference between the weather on the coast (South Haven) and the weather in Kalamazoo 30 miles East of that. The local TV station predicts scattered rain for the greater Kalamazoo area making me think not a good day to go to the big Lake but my friends in SH tell me it is dry and the sun is shining. Happened many times due to the Westerly winds hitting the hills West of Kalamazoo and dumping rain/snow because of it.

[Deleted another sidebar topic about how much error can be tolerated in particular employments. This is not a boating topic--jimh]
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Re: Accuracy of local television station weather forecasts for boating

Postby jimh » Wed Apr 11, 2018 6:33 pm

The topic of the accuracy of weather forecasts on local television stations became a long sidebar to another discussion about a boating topic. I have moved all the posts from the sidebar to this new topic in order to not clutter up the original topic.

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Re: Accuracy of Weather Forecasts On Local Television Stations

Postby jimh » Wed Apr 11, 2018 6:42 pm

DUTCH--because I don't watch local television stations, I don't get my weather information from them.

I have found that I can get weather information from respected sources on-line at no cost.

The fundamental nature of television broadcasting by over-the-air commercial television stations is to serve the public in their broadcast area. It is typical that a television station will be received in a 50-miles radius from its transmitter location. If we assume a mostly circular coverage pattern, in a 50-mile radius a station will cover an area of of about 25,000-square miles.

I don't think it is reasonable to require that a broadcast television station must provide weather data that is so granular in nature that every possible location within a 25,000-square-mile area is forecasted with very high accuracy. It is certain that the regulatory agency that oversees the licensing of broadcast television--the Federal Communications Commission--does not impose any sort of requirement that any weather information broadcast has to be entirely accurate and have enough granularity that every place in the station's area of coverage will be completely and accurately described.

If the local broadcast television station that you are able to receive is not providing you with weather information that meets your needs, you probably need to look for a different source of weather information. There are many options available now.

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Re: Accuracy of local television station weather forecastsRe: Accuracy of local television station weather forecasts for

Postby Jefecinco » Thu Apr 12, 2018 8:20 am

I've had good results from the Weather Underground web site. A feature I like is the ability to zero in on specific neighborhoods for current conditions. Forecasts are only about as good as the NWS, or merely good.

I'm fairly certain that our local TV forecasts are based on NWS forecasts despite claims the "weathermen" have earned degrees in the subject.

Broadcast television is a poor medium for information and only marginally better for entertainment.

Those of us who can remember forecasting from sixty years ago have to admit that today's forecasts, especially long range forecasts, are incredibly accurate.
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Re: Accuracy of local television station weather forecasts for boating

Postby rtk » Thu Apr 12, 2018 8:25 am

I am a bit of an amateur weather nerd- small boat coastal and offshore to 100 miles fishing/cruising etc makes it a necessity. Conditions can change quite drastically throughout the day so I look at the general weather dynamics nation wide.

I watch the weather channel each morning to see what the "national trend" is with regard to fronts and pressure systems.

I then go to http://www.weather.gov to look at the local forecast and the marine forecast. The marine forecast is vital because coastal weather in New Jersey can be quite different then inland weather due to the water vs. land temperature influence on local pressure gradients.

Wind direction and velocity is key to determining sea state so I mostly pay attention to wind forecasts.

It's all about fetch and wind velocity- get to know it well and you can avoid a very uncomfortable day on the water. This applies to large lakes and other bodies of water as well. Water depth/bottom contour makes a large difference also:

Fetch: 1. The area in which ocean waves are generated by the wind. Also refers to the length of the fetch area, measured in the direction of the wind. 2. In hydrologic terms, The effective distance which waves have traversed in open water, from their point of origin to the point where they break. The distance of the water or the homogenous type surface over which the wind blows without appreciable change in direction.

https://forecast.weather.gov/glossary.php?word=fetch

A nice sunny day can make for a miserable day on the water in Barnegat Bay if it is blowing 20 mph in a southerly or northerly direction. Southeast snot is the local vernacular. It only takes about an hour to kick the seas up when the southerly sea breeze comes a blowin' like clockwork in the summer when a relative high pressure/sunny weather is dominant.

Diurnal- Daily; related to actions which are completed in the course of a calendar day, and which typically recur every calendar day (e.g., diurnal temperature rises during the day, and diurnal falls at night).

https://forecast.weather.gov/glossary.php?word=DIURNAL

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Re: Accuracy of local television station weather forecasts

Postby Dutchman » Thu Apr 12, 2018 8:55 am

Jim--thanks for making this a separate thread.

Yes I don't watch local news either for the same reason you mention.

I too use weather-underground for the same reasons Butch mentions, they seem to be pretty accurate.

As I deal with weather on the east side of Lake Michigan I use a lot of the weather stations and the weather buoys on the Lake. The buoys are great for wave action and water temperature, and the stations (some on pier ends and lighthouses) are good for air and wind. Sometimes together with a real-time camera I know what to expect when going sailing and boating.

It is good to hear from from Rich that he takes good precaution when going out a ways on the ocean, as that must be a requirement for all venturing out more than 15 to 20 miles.

ASIDE to Jim - Our USPS (part of District 9) has offered Weather Courses that sometimes have been taught by or have one of the local TV station meteorologists as guest, always a good refresher and or new info for the boaters in our squadron.
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Re: Accuracy of local television station weather forecasts

Postby jimh » Thu Apr 12, 2018 9:45 am

I think the real topic here is this:

Should a recreational boater make decisions about navigating their boat based on watching broadcasts from commercial television stations of weather information contained as brief segments of five minutes or less in half-hour programs presenting general news information that occur sporadically during the day?

The computer-based navigation application I use, PolarView NS, has a wonderful feature: it can fetch GRIB weather forecast data for wind speed and direction and then overlay the wind data onto a navigation chart. The data can be obtained in various levels of granularity of time and geographic resolution. In my experience, these forecasts are very good predictors of actual wind.

I recall one instance in particular: we were staying in the harbor at Charlevoix, and had been there for two nights. The wind was unusually strong, so much so that the only boating we could do was in the protected bays on Lake Charlevoix. Going out on Lake Michigan was not an option for most of the last two days. The Marina was very busy and completely full, and there were no slips available for that evening. We probably could have stayed somewhere, along the seawall, as the harbormaster was very accommodating, but he just needed the slip we were in for a larger boat that had made reservations. And we actually preferred to get back to our home port.

Using the GRIB forecast for wind, I noticed that their model showed a significant drop in wind speed and a favorable change in direction was forecast to occur in a few hours. We told the harbormaster we planned to leave the slip then, and check on the lake conditions, which if favorable, would mean we'd not be staying that night; otherwise, we'd be back and try to fit in somewhere on the seawall.

At the predicted time for the wind shift, we departed Charlevoix and cautiously entered the open water of Lake Michigan. There we found the wind had reduced to the predicted speeds and shifted in the predicted direction, allowing us to make the 20-mile run across the top of Grand Traverse Bay in reasonable seas.

Having access to the GRIB model via download using the navigation application, a WiFi connection to the internet, and graphical representation of the model overlaid on a navigation chart enabled us to safely make the crossing.

The accuracy and granularity of the GRIB model forecast data far exceed any other source of wind information I am aware of. This data is available for free and access to it is beautifully implemented in PolarView NS. When planning any boating activity, using information from GRIB models will give you much more information than provided by a few minutes of weather information in a local television station's presentation of news.

I don't think any prudent mariner should base their safety at sea on what a commercial television station broadcast describes as the weather forecast, clearly aimed at a general population, covering a large area, and not specifically oriented toward mariners.

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Re: Accuracy of local television station weather forecasts

Postby dtmackey » Fri Apr 13, 2018 9:32 am

My concern with the local weather forecasts are the "hype" that is interjected. Too many times the actual weather has not lived up to the forecast and they never detail about what the forecast will be in the mountains just 90 miles north, so this forces me to get my information elsewhere.

Maybe it's just the New England area with the ocean temps and mountains that have a greater influence on the weather creating variables that are difficult to provide accurate forecasts.

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Re: Accuracy of local television station weather forecasts

Postby Dutchman » Fri Apr 13, 2018 11:06 am

dtmackey wrote:Maybe it's just the New England area with the ocean temps and mountains that have a greater influence on the weather creating variables that are difficult to provide accurate forecasts.


D---not just where you are. We have the same problem here in southern west Michigan with the big body of water to our west, Lake Michigan.
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Re: Accuracy of local television station weather forecasts for boating

Postby fno » Fri Apr 13, 2018 11:13 am

In and around North Central Florida and the Big Bend area, we use a number of sources for determining suitable boating weather. A lot depends on the activity and duration. An overnighter 100 miles out on the Gulf of Mexico requires a different set of information than a day in the shallows hunting scallops. That being said, online weather is much more informative than any broadcast news, another valuable but almost always flawed (1'-2' seas usually mean 2'-4') is the marine band weather broadcasts on VHF. Our pre trip planning also includes a look at the offshore weather and sea state bouys that are also online. Last but not least, is the Sirius satellite weather on my Simrad multifunction chartplotters. They offer real time weather conditions in and around the area while actually boating. It has kept us informed many times of typical Florida thunderstorms that can be at best unpleasant and worse life threatening.

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Re: Accuracy of local television station weather forecasts for boating

Postby rtk » Mon Apr 16, 2018 7:53 am

That [GRIB weather model feature in PolarView NS] is slick work there. What a great program to have available!

I generally limit my boating excursions to half-day to one-day durations. The boats I go offshore on do have weather service subscriptions (I believe Sirius integrated with radar abd chartplotters) so "surprise" thunderstorms can be avoided or mitigated. It's really cool to watch the fronts and be able to simply navigate a course that lessens the impact of the weather event.

On my 1966 16 Whaler I simply do not sail if there is a chance of weather that would lead to an uncomfortable day. I used to enjoy weather extremes in small vessels but I'm just getting to old for that. As the song goes the thrill is gone! Been there done that got the t-shirt- it just hurts to much these days!

I hear all on the mountain effect on weather- I have been spending a few weeks a year on Lake Champlain, Vermont trailering my 1966 16 Whaler fishing and exploring. I'm still trying to get my head wrapped around the weather up there. It's fun though- if I don't know or if I don't have confidence in the forecast I simply hang at the dock or take a ride enjoying the beauitiful area.

We did get a rare nice weather window this past Friday and Saturday at the Jersey Shore and I was able to launch and take a ride on Saturday to test the boat for a late April trip to Lake George, New York to try and coax a few salmon and lake trout on the boat. Sunday and today we are back to the miserable weather trend we have experienced the past month and a half. These low pressure systems have become tedious!

Hope everyone who is impacted by this latest storm system is fairing ok- my heart goes out to all- be safe!

House is shaking from thunderstorms as I type!

Rich

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Re: Accuracy of local television station weather forecasts for boating

Postby Dutchman » Tue Apr 17, 2018 12:52 pm

Rich, I understand and thanks for your mutual feelings.
Just snow and slippery roads here today thunderstorms moved East.
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Re: Accuracy of local television station weather forecasts for boating

Postby jimh » Fri Apr 20, 2018 10:53 am

The ability to fetch near-real-time weather RADAR data by subscribing to a service that transmits the data from satellite is another great method for boaters to get very accurate and up-to-the-minute weather data. In a narrative of one of many cruises we have made to the North Channel of Lake Huron, I mentioned using satellite weather data and illustrated an example of the display of weather RADAR overlaid on a navigation chart. See my article at

http://continuouswave.com/sail-logs/nc2008/

Here are two illustrations from that article:

Image
What we saw visually of the approaching weather system: some very tall and very dark clouds approaching.

Image
What we saw on the satellite-transmitted weather RADAR image: the thunderstorm center would pass to the North of our position. We have clear weather to the West, where we planned to continue the day's cruise.